An electro-mechanical steering device, especially intended for boats, of this type is known by SE-A-392 083, for example. The steering means consists of a common steering wheel and the steered element consists of a steering arm on a steering shaft to a rudder or a steerable propeller drive unit. The mechanical transmission consists of a steering gear coupled to the steering wheel and a cable rotationally driven thereby, which is connected to a ball bearing screw, where the rotational movement is converted into a linear movement which is coupled to a servo motor. The steering wheel is joined to the steering wheel shaft via a gap connection with a pole reversing switch which, within the gap range, if the steering wheel is turned, turns the switch on or off to start or stop the servo motor.
The advantage of such an electro-mechanical system is that it is simpler and less expensive than the more widely used hydraulic servo systems. It is simple to arrange for emergency steering in event of power failure. One disadvantage of the known system described here is, however, that it lacks an electrical feedback circuit which means that it is not suitable for dual command steering, for example, i.e. with a main steering station and an extra steering station, on the flybridge, for example. There is thus no information at the extra steering station concerning the rudder setting, and this means that the steering wheel position on the flybridge will never reflect the deflection of the rudder. The slightest movement of the steering wheel from a neutral position will deflect the rudder regardless of whether or not the rudder, when it is coupled over from the main steering station to the extra steering station, already has an extreme deflection. Thus, the steering wheel at the extra steering station in practice only functions as a switch.